Liquified natural gas (LNG) fueled combined cycle power plant and a (LNG) fueled gas turbine plant

• US 6,374,591 B1
• Filed: 07/31/1997
• Issued: 04/23/2002
• Est. Priority Date: 02/14/1995
• Status: Expired due to Term

• Current Assignee: Suez LNG NA LLC
• Original Assignee: Tractebel LNG North America LLC
• Inventors: Johnson, Paul C., Toombs, Edwin
• Primary Examiner(s): Casaregola, Louis J.
• Application Number:
  US08/903,576
• Time in Patent Office: 1,727 Days
• Field of Search: 60/390.2, 60/391.82, 60/394.65, 607/28, 62/502, 62/503
• US Class Current: 60/783
• CPC Class Codes: F01K 23/10 with exhaust fluid of one cycle heating the fluid in another cycle F01K17/025 takes precedence
• CPC Class Codes: F02C 7/143 before or between the compressor stages
• CPC Class Codes: F17C 2221/033 Methane, e.g. natural gas, CNG, LNG, GNL, GNC, PLNG
• CPC Class Codes: F17C 2223/0161 cryogenic, e.g. LNG, GNL, PLNG
• CPC Class Codes: F17C 2223/033 Small pressure, e.g. for liquefied gas
• CPC Class Codes: F17C 2225/0123 gaseous, e.g. CNG, GNC
• CPC Class Codes: F17C 2227/0135 Pumps
• CPC Class Codes: F17C 2227/0316 Water heating
• CPC Class Codes: F17C 2265/05 Regasification
• CPC Class Codes: F17C 2265/07 Generating electrical power as side effect
• CPC Class Codes: F17C 2270/0581 Power plants
• CPC Class Codes: F17C 9/02 with change of state, e.g. vaporisation
• CPC Class Codes: Y02E 20/16 Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]
• CPC Class Codes: Y02E 20/18 Integrated gasification combined cycle [IGCC], e.g. combined with carbon capture and storage [CCS]
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A process and system which improves the capacity and efficiency of a power plant. A LNG supply system fuels the plant. Gasified LNG in a combustor mixes with the air from an air compressor to provide the hot combustion gas for a gas turbine. The expanding LNG is used to chill a heat exchange fluid, e.g. water, which heat exchange fluid cools and densifies the intake air for the air compressor. Subsequently, the heat exchange fluid is used in another heat exchange step and is then re-chilled and recycled to cool and densify the intake air.

Claims

1. A method for enhancing the capacity and efficiency of a gas turbine plant which comprises:

flowing LNG into a regasifier/chiller;

flowing a heat exchange fluid into the regasifier/chiller to regasify the LNG and to chill the heat exchange fluid;

flowing the chilled heat exchange fluid through a heat exchange zone through which zone flows the intake air for an air compressor in the gas turbine plant, the heat exchange fluid cooling and densifying the intake air;

flowing the heat exchange fluid from the heat exchange zone through a heat recovery heat exchanger to warm the heat exchange fluid;

flowing the heat exchange fluid from the heat recovery heat exchanger back to the regasifier/chiller;

flowing the regasified LNG to a combuster in the gas turbine plant;

mixing the cooled densified air with the regasified LNG in the combuster to generate hot combustion gases;

flowing the hot combustion gases to a turbine in the gas turbine plant to drive the turbine; and

discharging hot exhaust gases from the turbine and flowing the hot exhaust gase, without heat exchange, directly to said heat recovery heat exchanger.

2. The method of claim 1 which comprises:

placing the heat exchange fluid in indirect heat exchange relationship with the intake air.

3. The method of claim 1 wherein the heat exchange fluid is a water/glycol mixture.

4. A method for enhancing the capacity and efficiency of a gas turbine plant which comprises:

flowing LNG into a regasifier/chiller;

flowing a heat exchange fluid into the regasifier/chiller to regasify the LNG and to chill the heat exchange fluid;

flowing the chilled heat exchange fluid through a heat exchange zone through which zone flows the intake air for an air compressor in the gas turbine plant, the heat exchange fluid cooling and densifying the intake air;

flowing the heat exchange fluid from the heat exchange zone through a heat recovery heat exchanger to warm the heat exchange fluid;

flowing the heat exchange fluid from the heat recovery heat exchanger back to the regasifier/chiller;

flowing the regasified LNG to a combuster in the gas turbine plant;

mixing the cooled densified air with the regasified LNG in the combuster to generate hot combustion gases;

flowing the hot combustion gases to a turbine in the gas turbine plant to drive the turbine; and

discharging hot exhaust gas from the turbine and flowing the hot exhaust gases to said heat recovery heat exchanger, wherein the heat exchange fluid is a water/glycol mixture and the temperature of the water/glycol mixture entering the regasifier/chiller is approximately 95°

F., the temperature of the water/glycol mixture exiting the regasifier/chiller is about 35°

F. and the regasified LNG exiting the regasifier/chiller is about 45°

F.

5. The method of claim 4 which comprises:

improving the capacity of the combined cycle plant in an amount of up to 9%.

6. The method of claim 4 which comprises:

increasing the efficiency of the combined cycle plant up to about 2%.

7. A LNG combined cycle plant which comprises:

a LNG fuel supply system which system includes;

a source of LNG;

a regasifier/chiller for the LNG in fluid flow communication with the source of LNG;

a gas turbine plant which comprises;

an air compressor;

an air intake duct upstream of said air compressor;

a heat exchanger disposed in heat exchange relationship with the air intake duct;

a gas turbine;

a combuster interposed between the air compressor and the gas turbine, the combuster providing the energy to drive the gas turbine;

a generator coupled to the gas turbine; and

means to exhaust the gas from the gas turbine;

a heat recovery heat exchanger downstream of the gas turbine;

means to flow the exhaust gas from the gas turbine, without heat exchange, directly into the heat recovery heat exchanger;

means to flow a heat exchange fluid through the system in a single continuous flow path which comprises;

means to flow the heat exchange fluid through the regasifier/chiller to chill the heat exchange fluid;

means to flow the heat exchange fluid from the regasifier/chiller and through the heat exchanger in the air intake duct to cool and density the intake air flowing through the air duct and into the compressor;

means to flow the heat exchange fluid from the heat exchanger and through the heat recovery heat exchanger to warm the heat exchanger fluid; and

means to flow the heat exchange fluid from the heat recovery heat exchanger and through the regasifier/chiller.

8. The plant of claim 7 which includes:

means to place the heat exchange fluid in indirect heat transfer relationship with the intake air.

9. A LNG combined cycle plant which comprises:

a LNG fuel supply system which system includes;

a source of LNG;

a regasifier/chiller for the LNG in fluid flow

communication with the source of LNG;

a gas turbine plant which comprises;

an air compressor;

an air intake duct upstream of said air compressor;

a heat exchanger disposed in heat exchange relationship with the air intake duct;

a gas turbine;

a combuster interposed between the air compressor and the gas turbine, the combuster providing the energy to drive the gas turbine;

a generator coupled to the gas turbine; and

means to exhaust the gas from the gas turbine;

a heat recovery heat exchanger downstream of the gas turbine;

means to flow the exhaust gas from the gas turbine into the heat recovery heat exchanger;

means to flow a heat exchange fluid through the system in a single continuous flow path which comprises;

means to flow the heat exchange fluid through the regasifier/chiller to chill the heat exchange fluid;

means to flow the heat exchange fluid from the regasifier/chiller and through the heat exchanger in the air intake duct to cool and densify the intake air flowing through the air duct and into the compressor;

means to flow the heat exchange fluid from the heat exchanger and through the heat recovery heat exchanger to warm the heat exchanger fluid;

means to flow the heat exchange fluid from the heat recovery heat exchanger and through the regasifier/chiller; and

wherein the heat exchange fluid is a primary heat exchange fluid wherein the gasifier/chiller is a first regasifier/chiller which comprises;

means for flowing a secondary heat exchange fluid between a second regasifier/chiller and the first regasifier chiller, the first and second regasifier/chillers in fluid flow and heat transfer relationship with one another, to cool the primary heat exchange fluid.

10. The plant of claim 9 wherein the secondary heat exchange fluid is a water/glycol mixture.

11. The plant of claim 9 which comprises:

means for flowing the secondary heat exchange fluid between the first and second regasifier/chillers in a closed loop.

12. A method for enhancing the capacity and efficiency of a gas turbine plant which comprises:

flowing LNG into a regasifier/chiller;

flowing a heat exchange fluid into the regasifier/chiller to regasify the LNG and to chill the heat exchange fluid;

flowing the chilled heat exchange fluid through a heat exchange zone through which zone flows the intake air for an air compressor in the gas turbine plant, the heat exchange fluid cooling and densifying the intake air;

flowing the heat exchange fluid from the heat exchange zone through a heat recovery heat exchanger to warm the heat exchange fluid;

flowing the heat exchange fluid from the heat recovery heat exchanger back to the regasifier/chiller;

flowing the regasified LNG to a combuster in the gas turbine plant;

mixing the cooled densified air with the regasified LNG in the combuster to generate hot combustion gases;

flowing the hot combustion gases to a turbine in the gas turbine plant to drive the turbine; and

discharging hot exhaust gases from the turbine and flowing the hot exhaust gases to said heat recovery heat exchanger,

wherein the heat exchange fluid remains in a liquid phase throughout the flow of heat exchange fluid into the regasifier/chiller, through the heat exchange zone, from the heat exchange zone through the heat recovery heat exchanger, and from the heat recovery heat exchanger back to the regasifier/chiller.

13. A LNG combined cycle plant that comprises:

a LNG fuel supply system which system includes;

a source of LNG;

a regasifier/chiller for the LNG in fluid flow communication with the source of LNG;

a gas turbine plant which comprises;

an air compressor;

an air intake duct upstream of said air compressor;

a heat exchanger disposed in heat exchange relationship with the air intake duct;

a gas turbine;

a combuster interposed between the air compressor and the gas turbine, the combuster providing the energy to drive the gas turbine;

a generator coupled to the gas turbine; and

means to exhaust the gas from the gas turbine;

a heat recovery heat exchanger downstream of the gas turbine;

means to flow the exhaust gas from the gas turbine into the heat recovery heat exchanger;

means to flow a heat exchange fluid in a liquid phase through the system in a single continuous flow path which comprises;

means to flow the heat exchange fluid through the regasifier/chiller to chill the heat exchange fluid;

means to flow the heat exchange fluid from the regasifier/chiller and through the heat exchanger in the air intake duct to cool and density the intake air flowing through the air duct and into the compressor;

means to flow the heat exchange fluid from the heat exchanger and through the heat recovery heat exchanger to warm the heat exchanger fluid; and

means to flow the heat exchange fluid from the heat recovery heat exchanger and through the regasifier/chiller.